Choke attachment for shotguns



July 24, 1962 R. M. cUTTS CHOKE ATTACHMENT FOR sHoTGUNs 2 Sheets-Sheet 1 Filed May 25. 1959 A Nv Sv i :llll

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R 0 f T5 WW W6 M m M w ATTORNEY July 24, 1962 R. M. @uns 3,045,379

CHOKE ATTACHMENT FOR SHOTGUNS Filed May 25, 1959 2 Sheets-Sheet 2 f INVENTO ATTORNEY I Jr'1ited StatesL Patent() 3,045,379 CHOKE ATTACHMENT FOR SHOTGUNS Richard M. Cutts, The Plains, Va. Filed May 25, 1959,.Ser. No; 815,662

` 2 Claims. (Cl. 42`-79) In the operation of shotgunsit has often been the practice to apply to the muzzle thereof a straight laterally ported tube having an internal diameter greater than the bore of the shotgun lto which it is aiTlXed, which constitutes an expansion chamber to disperselgases as Vthe shot column passes through the tube and into the choke affixed to the outer end thereof. These chambers may take any number of different forms, some provided with spaced slots, openings and the-like topermit rapid dispersal of the gases of propulsion as soon as they have left the muzzle of the gun in ,order .to better control the shot column as it passes into the choke tube, as well as to reduce recoil.

Such devices have met with considerable success and are extensively lsed, however, these tubes, expansion chambers, etc. do not function as wellas formerly due to the change and improvement in the loading of shotgun shells. v t

Formerly. the powder wad or wads of the shotshell Vwere more lightly constructed than those in use at present,

and the turbulent action of the gases within the-expansion chamber when being exhausted through the ports vthereof resulted in disintegration or partial disintegration, and expansion of the wad laterally. Naturally, when the wad was disintegrated or partially disintegrated, it was disposed of because itlost forward velocity and had no deleterious effect upon the shot column. However, in those instances where disintegration/or partial disintegration Vdid not occur and the wad was expanded to'a sizeV greater than the internal diameter of the forward choke, it is obvious that due Yto this increased diameterY of the wad it was retarded in its movement in a forward direction by the smaller diameter of the choke tube. This resulted in a decreased velocity of theA powder wad in a forward direction Aso that it never caught up to the shot column, pancaking the rear end of the latter and thus upsetting the said column once it had beeny rectified by the choke. l

Powder wads as used lat presenta're made of either highly compressed ber or of plastic materials which are practically indestructible, and the above explained desirable gas actions upon'the powder wadsare insuflicient to bring about disintegrationor destruction ofV these wads.

1 The present invention contemplates fthe useof means of simple nature for bringing about -actioniof the propellantgases in the expansionch'amber upon the powder wads whereby the above mentioned disadvantageous effects of these wads upon the rear of the shot column are v obviated. v

` An important object of the invention is to provide means withirithe expansion chamber whereby the' pro-' pellant gases are utilizedto bring about a deectio'nof thepowder wads'laterally Vof the chamberandA the shot column, and to dispose the powderwads in suchA position thatthey will trail thesht Vcolumn without disadvantageously affecting the corrected diameter of the shot column Y bodiment of my invention applied thereto,

FIG. 2 is alview similar to FIG. l and illustrating the several positions assumed by the powder wad as the shot column passes through the chamber,

FIG. 3 is a view similar to FIG. 1 and showing substantially the liual position assumed by the shot wad in trailing the shot column through the choke member,

FIG. 4is a transverse sectional view taken substantially on line 4 4 of FIG. l,

FIGS is 'a detail vperspective view of the abutment or wall member utilized in carrying out the invention,

FIG. 6 is an enlarged `fragmentary longitudinal sectional view taken through the forward end of the expan- 'sion chamber and the rear end of the choke member and illustrating the application to the chamber of a modified form of the invention,

FIG. 7 is a perspective view'illustrating the form of FIG.- 12 is a perspective view of a further modiiication of the invention, and .n

FIG. 13 is 'a fragmental section taken longitudinally through the bottom of the device shown in FIG. 12. i

In the preferred embodiment of the invention, the shotgun muzzle indicatedl at 10 has attached thereto in any desired manner the inner end of an expansion chamber or tube' 11, the sides of which may be ported or`provided with spaced'slots or openings 12 throughout substantiallyV its Vlength to permit rapid dispersion ofthe gases of propulsionffor the accomplishment of results well known in the The outer or forward end of the chamber '11 has Aa conventional choke member 13 attached thereto in any desired manner, threads being shown in the present instance.v

In the present embodiment of the invention I provide within this 'expansion chamber a wallnor abutment member represented generally at 14 disposed transversely of said chamber and which projects inwardly from the inner periphery 40 of the chamber a suitable distance beyond the muzzle of the gun and partway around and conforming to said inner periphery and between adjacent dischargejports or openings 12.. With reference to FIGS; l to"5 inclusive, it will be observed that lengthwise this abutment or wall is of substantially semi-circularV construction having its inner and outer edges 30-31V conforming to theinner surface 40 curvature 'of the tube 11 and is formedof suitable'me'tal of ample'strength to withstand the pressures to'wliich it will be subjected when in use, and may be attached rmly in any desired manner, as by welding 42to the interior of theV expansion chamber at that portion of the latter preferably where no ports exist; `In the present instance, this Wall orY abutment member is shown as secured'to'the bottom or closed wall of the expansion chamber but it .will be'understo'od that `it may be located'at any yother desired position therein. It will also be observed that'the thickness or height of this wall or abutment issuch as not to be impinged by the shot column as it passes through the chamber and into lthe choke member, the distance between the inner edge 30 and the outer edge 3lV of wall 14 being less than one-half the distance from the airis of the tube to the inner periphery 40- thereof. With the wall or abutment thuslocated, it is obvious that the propellant gases, having been liberated in the expansion chamber and movl Patented Julya-t, 1962- ing forwardly faster than the shot column, taking the course indicated by the arrows, strike the rearward face of the abutment or wall 14 and will be diverted inwardly of the chamber as shown by the arrows so as to bring about lateral pressure upon the powder wad 15 which is closely following the shot column. It will be understood that this action of the gases diverted by the wall or abutment is insutlicient to disturb the relatively heavy shot column in its forward movement, however, it has very material diverting effect upon the lighter following powder wad, causing it to be deflected off-center in its forward movement toward, the choke tube. Also, the action of the gases diverted by the abutment or wall 14 in conjunction with other gases which are moving in substantially a forward direction, causes the powder wad to tilt as it moves forwardly within the chamber or tube as shown in FIGS. 2 and 3 of the drawings. 'Ihis tilting effect on the powder wad has a further result of causing a portion of the propellant gases which are driving the Wad in a forward direction to escape around the sides of the wad thereby reducing its forward velocity. This velocity is further reduced by the fact'that the wad having been deflected olf-center impinges on the rearward edge of the choke 13 causing it to take a position substantially as that illustrated in FIG. 3 of the drawings. It is obvious that these actions upon the powder wad result in materially reducing its velocity in a'forward direction so that it trails the heavier, faster moving shot column by a substantial distance, thereby preventing the objectionable pancaking et'r'ect upon the shot column after it has once been rectified to the desired dimension by the choke.

It will be understood that in those instances where a plurality of powder wads are used, the effects are the same as described above, however, for the sake of simplicity only one wad has been shown in the present illustration. a Y

While in the present discolsure expansion chambers having perforated wall'sections are closed, it will be understood that the inventive idea is equally applicable to imperforate chambers or tubes and will perform in precisely the same manner in vdiverting and tilting the powder wad when passing'through the member.

In FIGS. 6`and 7` of the drawing,`there is illustrated a modified form of the invention, wherein the expansion tube 11 is provided with an insert readily applicable thereto to provide the abutment or gas diffusion wall as has heretofore been described. In this form of the invention, a collar indicated at 15', conforming substantially to the inner diameter of the tube 11, is provided with spaced rearwardly projecting arms or supports 16, the collar snugly fitting within the tube.y The rearward ends of the arms or supporting members 16 carry an upwardly projecting wall or abutment 17 extending partially around the inner circumference of theV tube and snugly engaging the inner wall thereof, thus providing the abutment against which the propellant gases engage and operate inthe manner heretofore described. In this form of the invention, the collar 1S' and`its integral supporting arms A16 may be formed of light metal with the collar split longitudinally as at 18 so that it may snugly tit within the expansion chamber with an expansion lit, the forward end of the collar abutting the rear or inner end of the choke member 13 and being thus securely held `in place.

In other instances, such as shown in FIG. 8, the collar may be so designed as to threadedly engage within the forward end of the expansion chamber and to rmly aix itself thereto as indicated at 19. In all other respects, the collar and its abutment wall and arms are the same as the structures shown in FIGS. 6 and 7.

In FIG. 9 of the drawings a further modification of the invention is illustrated, wherein a plurality of abutments or walls 20, of the type illustrated in FIGS. 1 to inclusive, are shown. In this form of the invention the abutments will be disposed between ports 12 in alternate or staggered relationship in the length of the expansion tube. By arranging the abutment walls in this manner, it is apparent that the forward and rapidly moving gases within the chamber will be diverted alternately in opposite directions toward the axis of the tube, thus bringing about various lateral movements of the powder wad, as well as twisting and turning of the same as it travels in thel direction of the choke. Moreover, the plurality of walls bringing about this diversion of the gas flow .will obviously reduce the forward speed of the powder Wad.

FIGS. l0 and 1l show a still further modification of the invention, wherein the' wall or abutment, indicated at 21, is formed in the wall of the expansion tube itself. This wall is formed by cutting an incision partway around the tube and bending the edge of the cutaway portion inwardly so that it extends into the tube and constitutes the desired abutment or wall for inwardly deflecting the forwardly moving gases in the accomplishment of the results heretofore detailed.

FIGS. l to 11 inclusive of the drawings illustrate the abutments having their operative faces or walls disposed at substantially right angles to the axis of the expansion tube, but it will be understood that such faces or walls may be inclined or beveled in the manner shown and described in connection with FIGS. l2 and 13.

FIGS. 12 and 13 of the drawing show a further modiication of the invention, wherein an imperforate segmental sleeve 25 having arcuate expansible arms 26 at one end thereof conforms to the inner circumference of the gun barrel. It will be understood that the sleeve and the arms will be slightly greater than the internal diameter of the gun barrel so that when forced into the same the expansive pressure of the arms 26 will friction-ally engage with the inner walls of the barrel. The sleeve 2S may have a beveled surface 27 at its inner end, the inclination of which may vary in accordance with requirements, but may assume the angle such as is shown in FIG. 13. The angularity of this wall is inwardly and forwardly of the expansion chamber as will be understood, and it is obvious that the gases of propulsion striking this inclined wall will be diverted inwardly toward the axis of the sleeve and -against the rearfend of the shot column, thus deiiectng the powder wad in the manner heretofore described in connection with the otherL forms of the invention. It will beapparent that the imperforate sleeve portion 25 will cover portions of those ports 12 in the expansion tube 11 which it overlies. The gases of propulsion striking this inclined surface will have the effect of forcing the sleeve into tight frictional engagement with the inner circumference of the expansion tube, thus tending to maintain the sleeve in the desired and proper position. It is apparent also that a substantially semi-'cylindrical imperforate sleeve, such as is shown in FIG. 12, without thearrns 26 may equally as effectively be utilized in the accomplishment of the desired results. Such a sleeve would be inserted in the expansion chamber and alixed at the proper position therein by any of the methods heretofore disclosed.

From the foregoing it is apparent that I have provided means of simple nature for application to the expansion chamber to bring about the beneficial results here fully explained and emphasized in retarding the forward advance of the powder wads as well as moving them offcenter within the chamber and in a tilted manner in passing through the choke member.

1. An attachment for Shotguns comprising a cylindrical expansion tube open at both ends, a choke member at one end of said tube, an arcuate abutmentmember having outer and inner edges concentric with said tube disposed transversely within said tube inwardly, from the ends thereof `and with its outer edge aixed to the inner periphery of said tube, the distance between the outer and inner edges of said abutment member being less than one-half the distance from the axis of the tube to the inner periphery thereof.

2. An attachment for Shotguns comprising a cylindrical expansion tube open at both ends, 1a choke member at one end of said tube, an arcuate abutment member having outer and inner edges concentric with said tube disposed transversely therein inwardly from the tube ends and with its outer edge laiixed to the inner periphery of said tube, the distance between the inner and outer edges of said abutment member being less than one-half the distance from the axis of the tube to the inner periphery thereof, and the ends of said `abutment member terminating at diametrically opposite points Within said tube.

References Cited in the die of this patent UNITED STATES PATENTS 

